<!doctype html public "-//W3C//DTD W3 HTML//EN"> <html><head><style type="text/css"></style><title>RE: More CC vs RC questions was RE: Killer Octave & Pitch</title></head><body> <div>Hi all,</div> <div><br></div> <div>Ron N wrote;</div> <div><br></div> <blockquote type="cite" cite>No, because you aren't relying solely on panel compression for that stiffness increase. You can make the ribs as stiff or as flexible as you like to build in whatever spring rate you think you want with the RC&S assembly. In the RC&S assembly, you can also easily produce considerably different spring rates in different parts of the scale.</blockquote> <div><br></div> <div>Indeed, the spring rate must vary throughout the scale. It must have a lower rate in the bass to allow wider panel excursions, and stiffer in the treble to accommodate the much small amplitude of panel movement required for a given sound pressure level.</div> <div><br></div> <div>This is the second time that Ron N has mentioned spring rates and it is a most important point IMO. The spring rate, mass combination/distribution and the hysteresis characteristics of the sound board assembly (which Sarah Fox mentioned in her thoughtful post) will come together to produce the resultant tonal characteristics, to a large extent.</div> <div><br></div> <div>Rick B wrote;</div> <div><br></div> <blockquote type="cite" cite>Oh it holds up,,, as far as the reasoning goes. But stiffness, as you know, and for that matter spring rate is not all one is concerned with.</blockquote> <div><br> Agreed, it isn't.<br> </div> <blockquote type="cite" cite> You have the mass side of the equation to figure in.... at the very least.</blockquote> <div><br></div> <div>Yes we do, plus hysteresis.</div> <div><br></div> <blockquote type="cite" cite> You can easily achieve similar stiffness levels I would assume... with two different assemblies ( a CC and an RC&S) at least for a given RH,</blockquote> <div><br></div> <div>This should be do-able.</div> <div><br></div> <blockquote type="cite" cite> but achieving that and at the same time the same stiffness to mass relationships is another matter.</blockquote> <div><br></div> <div>It is not a 'another matter'. If you have determined a certain spring rate but would like more mass you can use more, lower and wider ribs, and your mass will be increased at a given stiffness. If you want less mass for the same stiffness (spring rate) you can use less, deeper and narrower ribs. Its a simple matter to arrive at the spring rate and mass relationship required, using RC construction. Furthermore, I believe that the stiffness of ribs should ideally be varied along their length. The rib should be stiffer under the bridges (where most CC boards collapse in short order), getting gradually weaker as we move from the bridges to the ends of the rib. The tapering of rib strength is a cake walk when building an RC& S board. While the CC building school can contour the panel thickness to increase the stiffness under the bridges, it is more of a 'blunt instrument'.</div> <div><br></div> <blockquote type="cite" cite>So varying panel thickness to achieve similar stiffness would probably insure dissimilar mass.</blockquote> <div><br></div> <div>Varying the panel thickness, to achieve a certain level of stiffness, has been the most usual method of controlling stiffness for the CC building school. The hysteresis loss matter, which Sarah raised, is an interesting one as well.</div> <div><br></div> <div>At 2:28 PM +0100 14/2/05, Richard Brekne wrote:</div> <blockquote type="cite" cite><br></blockquote> <blockquote type="cite" cite>When someone makes a RC&S board and puts it into a Steinway D rim, and puts the darned thing on the stage of Carnegie Hall and fools everyone with its <<authentic Steinway sound>></blockquote> <div><br></div> <div>Outside of the extensive 'cloning' school, who would want to build an authentic Steinway sound - I certainly don't? And I don't expect to see an RC&S  boarded instrument on the Carnegie Hall concert platform anytime soon. I certainly have no interest in fooling anybody. Besides, if you built a different design into a Steinway piano and failed to acknowledge it on the piano, you'd have the S&S legal team trying to put you out of business ASAP. I and a number of others have experience this potential drama first hand. Fortunately, I always fix a label to the piano stating any modifications, so their team had nothing to stand on in 1996. I've already built an RC&S board into a D and, as expected, it certainly didn't sound like a Steinway.</div> <div><br></div> <div>I think folks should stop worrying about the risk of RC & S construction causing the sky to fall in. Let's give the idea a serious evaluation. At present the mainstream manufacturers have joined in, in condemning the RC & S idea. There was a time when shaped ribs were being similarly condemned. Today, many manufacturers are profiling their ribs. Some are even doing it to the actual ribs, and not just in the brochure.</div> <div><br></div> <div>Today is the second recording day (of 5) of Scott Davie's second CD to be recorded on an Overs 225 piano. In this case the piano is the RC&S boarded Overs no. 5 (the samples on the website are of no. 3).  For this CD, Scott is recording Massorgsky's<i> Pictures at an Exhibition</i> and Rachmaninoff's first piano sonata (a monster work). It should be available for sale sometime around mid year 05. Yesterday, the recording team spent the first 2.5 hours getting the recorded sound to a close match of the piano. Five of us finally agreed on the balance, Scott Davie (recording artist), Lyle Chan (ABC Classics executive producer), Thomas Grubb (producer), Christian Huff-Johnston (engineer) and myself as piano technician. Scott recorded<i> Pictures</i> from memory yesterday. I was most impressed when Tom would make suggestions to Scott," from bar *** to ***", and he would just pick up from that point for another 'take' without referring to the score. Its wonderful to observe real talent in mid-career.</div> <div><br></div> <div>Ron O.</div> <x-sigsep><pre>-- </pre></x-sigsep> <div><font face="Times New Roman" size="+1" color="#0000FF"><b>OVERS PIANOS - SYDNEY</b></font></div> <div><font color="#000000"><i>   </i></font><font color="#0000FF"><i>Grand Piano Manufacturers</i></font><font color="#000000"><br> _______________________</font></div> <div><font size="-2" color="#000000"><br> </font><font color="#000000">Web http://overspianos.com.au</font></div> <div><font color="#000000">mailto:ron@overspianos.com.au<br> _______________________</font></div> </body> </html>